CA2505285A1 - Aluminium electrowinning cells with metal-based anodes - Google Patents
Aluminium electrowinning cells with metal-based anodes Download PDFInfo
- Publication number
- CA2505285A1 CA2505285A1 CA002505285A CA2505285A CA2505285A1 CA 2505285 A1 CA2505285 A1 CA 2505285A1 CA 002505285 A CA002505285 A CA 002505285A CA 2505285 A CA2505285 A CA 2505285A CA 2505285 A1 CA2505285 A1 CA 2505285A1
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- weight
- cell
- aluminium
- anode
- fluoride
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Classifications
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
- C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
- C25C3/18—Electrolytes
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
- C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
- C25C3/08—Cell construction, e.g. bottoms, walls, cathodes
- C25C3/12—Anodes
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electrolytic Production Of Metals (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Primary Cells (AREA)
Abstract
A cell for the electrowinning of aluminium comprises a metal-based anode (10) containing at least one of nickel, cobalt and iron. The anode (10) may be covered with an applied or an integral hematite-based layer and/or a cerium oxyfluoride-based outermost coating. The cell contains a fluoride-containing molten electrolyte (5) at a temperature below 950~C, in which the anode (10) is immersed and which consists of: 6.5 to 11 weight% dissolved alumina; 35 to 44 weight% aluminium fluoride; 38 to 46 weight% sodium fluoride; 2 to 15 weight% potassium fluoride; 0 to 5 weight% calcium fluoride; and 0 to 5 weight% in total of one or more further constituents. An anode stem (14b) containing nickel and/or iron can be used to suspend the anode (10) in the electrolyte (5) facing a cathode (21,21A,25) that has an aluminium-wettable surface (20), in particular a drained horizontal or inclined surface.
Claims (28)
1. A cell for electrowinning aluminium from alumina, comprising:
- a metal-based anode having an outer part that contains at least one of nickel, cobalt and iron, the outer part having an electrochemically active oxide-based surface; and - a fluoride-containing molten electrolyte in which the active anode surface is immersed, the electrolyte being at a temperature below 950°C, in particular in the range from 910° to 940°C, and consisting of:
- 6.5 to 11 weight% dissolved alumina;
- 35 to 44 weight% aluminium fluoride;
- 38 to 46 weight% sodium fluoride;
- 2 to 15 weight% potassium fluoride;
- 0 to 5 weight% calcium fluoride; and - 0 to 5 weight% in total of one or more further constituents.
- a metal-based anode having an outer part that contains at least one of nickel, cobalt and iron, the outer part having an electrochemically active oxide-based surface; and - a fluoride-containing molten electrolyte in which the active anode surface is immersed, the electrolyte being at a temperature below 950°C, in particular in the range from 910° to 940°C, and consisting of:
- 6.5 to 11 weight% dissolved alumina;
- 35 to 44 weight% aluminium fluoride;
- 38 to 46 weight% sodium fluoride;
- 2 to 15 weight% potassium fluoride;
- 0 to 5 weight% calcium fluoride; and - 0 to 5 weight% in total of one or more further constituents.
2. The cell of claim 1, wherein the electrolyte contains 7 to 10 weight% alumina.
3. The cell of claim 1 or 2, wherein the electrolyte contains 36 to 42 weight% aluminium fluoride, in particular 36 to 38 weight.
4. The cell of any preceding claim, wherein the electrolyte contains 39 to 43 weight% sodium fluoride.
5. The cell of any preceding claim, wherein the electrolyte contains 3 to 10 weight% potassium fluoride, in particular 5 to 7 weight%.
6. The cell of any preceding claim, wherein the electrolyte contains 2 to 4 weight% calcium fluoride.
7. The cell of any preceding claim, wherein the electrolyte contains up to 3 weight% of said one or more further constituents.
8. The cell of any preceding claim, wherein said one or more further constituents comprise at least one fluoride selected from magnesium fluoride, lithium fluoride, cesium fluoride, rubidium fluoride, strontium fluoride, barium fluoride and cerium fluoride.
9. The cell of any preceding claim, wherein the electrolyte contains alumina at a concentration near saturation on the active anode surface.
10. The cell of any preceding claim, comprising a cathode that has an aluminium-wettable surface, in particular a horizontal or inclined drained surface.
11. The cell of claim 10, wherein the cathode has an aluminium-wettable coating that comprises a refractory boride and/or an aluminium-wetting oxide.
12. The cell of any preceding claim, wherein the anode has a metallic or cermet body and an oxide layer on the anode body.
13. The cell of any preceding claim, wherein the anode consists predominantly of iron and is optionally covered with an integral iron oxide-based layer.
14. The cell of claim 13, wherein the anode body is made from an alloy consisting of:
- 65 to 95 weight% iron, in particular 75 to 90 weight%;
- 2 to 10 weight% aluminium, in particular 3 to 6 weight% ;
- 0 to 5 weight% niobium, in particular 2 to 4 weight%;
- 0 to 3 weight% hafnium, in particular 1 to 2 weight%;
- 0 to 15 weight% in total of nickel and/or cobalt, in particular 0 to 10 weight%;
- 0 to 6 weight% copper, in particular 0 to 4 weight%;
and - 0 to 2 weight% in total of further constituents, in particular 0.5 to 1 weight%.
- 65 to 95 weight% iron, in particular 75 to 90 weight%;
- 2 to 10 weight% aluminium, in particular 3 to 6 weight% ;
- 0 to 5 weight% niobium, in particular 2 to 4 weight%;
- 0 to 3 weight% hafnium, in particular 1 to 2 weight%;
- 0 to 15 weight% in total of nickel and/or cobalt, in particular 0 to 10 weight%;
- 0 to 6 weight% copper, in particular 0 to 4 weight%;
and - 0 to 2 weight% in total of further constituents, in particular 0.5 to 1 weight%.
15. The cell of any one of claims 1 to 12, wherein the anode body is made from a nickel and/or cobalt-based alloy.
16. The cell of claim 15, wherein the anode body is made from an alloy consisting of:
- 50 to 65% in total of nickel and/or cobalt, in particular 55 to 60 weight%;
- 25 to 40 weight% iron, in particular 30 to 35 weight%;
- 3 to 11 weight% copper, in particular 5 to 9 weight%;
- 1 to 3 weight% aluminium, in particular 2 to 3 weight%;
- 0 to 2 weight% niobium, in particular 0 to 1 weight%;
- 0 to 2 weight% hafnium, in particular 0 to 1 weight%;
and - 0 to 2 weight% in total of further constituents, in particular 0.5 to 1 weight%.
- 50 to 65% in total of nickel and/or cobalt, in particular 55 to 60 weight%;
- 25 to 40 weight% iron, in particular 30 to 35 weight%;
- 3 to 11 weight% copper, in particular 5 to 9 weight%;
- 1 to 3 weight% aluminium, in particular 2 to 3 weight%;
- 0 to 2 weight% niobium, in particular 0 to 1 weight%;
- 0 to 2 weight% hafnium, in particular 0 to 1 weight%;
and - 0 to 2 weight% in total of further constituents, in particular 0.5 to 1 weight%.
17. The cell of claim 15 or 16, wherein the anode body is covered with an integral iron oxide-based layer containing oxides of iron and at least one of nickel and cobalt oxides, and optionally at least one oxide of one or more further metals, present in the following amounts calculated as weight% of the metals:
- 65 to 99 weight% iron, in particular 80 to 95 weight%;
- 1 to 35 weight% in total of nickel and/or cobalt, in particular 5 to 20 weight%; and - 0 to 3 weight% in total of said one or more further metals, in particular 0 to 1.5 weight%.
- 65 to 99 weight% iron, in particular 80 to 95 weight%;
- 1 to 35 weight% in total of nickel and/or cobalt, in particular 5 to 20 weight%; and - 0 to 3 weight% in total of said one or more further metals, in particular 0 to 1.5 weight%.
18. The cell of any preceding claim, wherein the anode comprises an applied iron oxide-based coating.
19. The cell of claim 18, wherein the anode coating contains Fe2O3 and optionally: at least one dopant selected from TiO2, ZnO and CuO and/or at least one inert material selected from nitrides and carbides.
20. The cell of any preceding claim, wherein the anode is coated with a cerium oxyfluoride-based outermost coating.
21. The cell of any preceding claim, wherein the anode is suspended in the electrolyte by a stem containing nickel and/or iron.
22. The cell of claim 21, wherein the stem has a core containing nickel and/or iron which is covered with an applied oxide coating, in particular an applied coating containing aluminium oxide and titanium oxide.
23. The cell of claim 21 or 22, wherein the core of the stem comprises a copper-based inner part and an outer part containing nickel and/or iron.
24. The cell of any preceding claim, comprising at least one component that contains a sodium-active cathodic material, such as elemental carbon, said sodium-active cathodic material being shielded from the electrolyte by a sodium-inert layer to inhibit the presence in the molten electrolyte of soluble cathodically-produced sodium metal that constitutes an agent for dissolving the active oxide-based anode surface.
25. A cell according to claim 1, comprising:
A) a metal-based anode having an outer part that has an electrochemically active oxide-based surface and that is made from an alloy consisting of:
- 75 to 90 weight% iron;
- 3 to 6 weight% aluminium;
- 0 to 4 weight% in total of niobium and/or hafnium;
- 0 to 10 weight% in total of nickel and/or cobalt;
- 0 to 4 weight% copper: and - 0.5 to 1 weight% in total of further constituents;
or - 55 to 60 weight % in total of nickel and/or cobalt;
- 30 to 35 weight% iron;
- 5 to 9 weight% copper;
- 2 to 3 weight% aluminium;
- 0 to 1 weight % in total of niobium and/or hafnium;
and - 0.5 to 1 weight% in total of further constituents;
B) an anode stem for suspending the anode in the electrolyte, the stem containing nickel and/or iron and being covered with a coating of aluminium oxide and titanium oxide;
C) a fluoride-containing molten electrolyte in which the active anode surface is immersed and which is at a temperature in the range from 910° to 940°C and which consists of:
- 7 to 10 weight% dissolved alumina;
- 36 to 42 weight% aluminium fluoride;
- 39 to 43 weight% sodium fluoride;
- 3 to 10 weight% potassium fluoride, in particular 3 to 7 weight%;
- 2 to 4 weight% calcium fluoride; and - 0 to 3 weight% in total of one or more further constituents;
and D) a cathode having an aluminium-wettable surface, in particular a drained horizontal or inclined surface, formed by an aluminium-wettable coating of refractory hard material and/or aluminium-wetting oxide.
A) a metal-based anode having an outer part that has an electrochemically active oxide-based surface and that is made from an alloy consisting of:
- 75 to 90 weight% iron;
- 3 to 6 weight% aluminium;
- 0 to 4 weight% in total of niobium and/or hafnium;
- 0 to 10 weight% in total of nickel and/or cobalt;
- 0 to 4 weight% copper: and - 0.5 to 1 weight% in total of further constituents;
or - 55 to 60 weight % in total of nickel and/or cobalt;
- 30 to 35 weight% iron;
- 5 to 9 weight% copper;
- 2 to 3 weight% aluminium;
- 0 to 1 weight % in total of niobium and/or hafnium;
and - 0.5 to 1 weight% in total of further constituents;
B) an anode stem for suspending the anode in the electrolyte, the stem containing nickel and/or iron and being covered with a coating of aluminium oxide and titanium oxide;
C) a fluoride-containing molten electrolyte in which the active anode surface is immersed and which is at a temperature in the range from 910° to 940°C and which consists of:
- 7 to 10 weight% dissolved alumina;
- 36 to 42 weight% aluminium fluoride;
- 39 to 43 weight% sodium fluoride;
- 3 to 10 weight% potassium fluoride, in particular 3 to 7 weight%;
- 2 to 4 weight% calcium fluoride; and - 0 to 3 weight% in total of one or more further constituents;
and D) a cathode having an aluminium-wettable surface, in particular a drained horizontal or inclined surface, formed by an aluminium-wettable coating of refractory hard material and/or aluminium-wetting oxide.
26. A method of electrowinning aluminium in a cell as defined in any preceding claim, comprising electrolysing the dissolved alumina to produce oxygen on the anode and aluminium cathodically, and supplying alumina to the electrolyte to maintain therein a concentration of dissolved alumina of 6.5 to 11 weight%, in particular 7 to 10 weight%.
27. An aluminium electrowinning anode made from an alloy consisting of:
- 65 to 95 weight% iron, in particular 75 to 90 weight%
or 90 to 95 weight%;
- 2 to 10 weight% aluminium, in particular 3 to 6 weight% or 5 to 10 weight%;
- 0 to 5 weight% niobium, in particular 2 to 4 weight%;
- 0 to 3 weight% hafnium, in particular 1 to 2 weight%;
- 0 to 15 weight% in total of nickel and/or cobalt, in particular 0 to 10 weight%;
- 0 to 6 weight% copper, in particular 0 to 4 weight%;
and - 0 to 2 weight% in total of further constituents, in particular 0.5 to 1 weight%, wherein the total amount of niobium, hafnium and further constituents is in the range from 0.25 to 3 weight%, in particular 0.75 to 2.5 weight%.
- 65 to 95 weight% iron, in particular 75 to 90 weight%
or 90 to 95 weight%;
- 2 to 10 weight% aluminium, in particular 3 to 6 weight% or 5 to 10 weight%;
- 0 to 5 weight% niobium, in particular 2 to 4 weight%;
- 0 to 3 weight% hafnium, in particular 1 to 2 weight%;
- 0 to 15 weight% in total of nickel and/or cobalt, in particular 0 to 10 weight%;
- 0 to 6 weight% copper, in particular 0 to 4 weight%;
and - 0 to 2 weight% in total of further constituents, in particular 0.5 to 1 weight%, wherein the total amount of niobium, hafnium and further constituents is in the range from 0.25 to 3 weight%, in particular 0.75 to 2.5 weight%.
28. An aluminium electrowinning anode made from an alloy consisting of:
- 50 to 65% in total of nickel and/or cobalt, in particular 55 to 60 weight%;
- 25 to 40 weight% iron, in particular 30 to 35 weight%;
- 3 to 9 weight% copper, in particular 5 to 7 weight%;
- 1 to 3 weight% aluminium, in particular 2 to 3 weight%;
- 0 to 2 weight% niobium, in particular 0 to 1 weight%;
- 0 to 2 weight% hafnium, in particular 0 to 1 weight%;
and - 0 to 2 weight% in total of further constituents, in particular 0.5 to 1 weight%, wherein the total amount of niobium, hafnium and further constituents is in the range from 0.25 to 5 weight%, in particular 1.5 to 3 weight%.
- 50 to 65% in total of nickel and/or cobalt, in particular 55 to 60 weight%;
- 25 to 40 weight% iron, in particular 30 to 35 weight%;
- 3 to 9 weight% copper, in particular 5 to 7 weight%;
- 1 to 3 weight% aluminium, in particular 2 to 3 weight%;
- 0 to 2 weight% niobium, in particular 0 to 1 weight%;
- 0 to 2 weight% hafnium, in particular 0 to 1 weight%;
and - 0 to 2 weight% in total of further constituents, in particular 0.5 to 1 weight%, wherein the total amount of niobium, hafnium and further constituents is in the range from 0.25 to 5 weight%, in particular 1.5 to 3 weight%.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IB0300662 | 2003-02-20 | ||
| IBPCT/IB03/00662 | 2003-02-20 | ||
| PCT/IB2004/000431 WO2004074549A2 (en) | 2003-02-20 | 2004-02-18 | Aluminium electrowinning cells with metal-based anodes |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2505285A1 true CA2505285A1 (en) | 2004-09-02 |
| CA2505285C CA2505285C (en) | 2012-07-17 |
Family
ID=32894011
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2505285A Expired - Fee Related CA2505285C (en) | 2003-02-20 | 2004-02-18 | Aluminium electrowinning cells with metal-based anodes |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP1608798A2 (en) |
| CA (1) | CA2505285C (en) |
| NO (1) | NO20054308L (en) |
| NZ (1) | NZ540408A (en) |
| WO (1) | WO2004074549A2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007105125A2 (en) * | 2006-03-10 | 2007-09-20 | Moltech Invent S.A. | Aluminium electrowinning cell with enhanced crust |
| CN102149853B (en) | 2008-09-08 | 2014-01-08 | 力拓艾尔坎国际有限公司 | Metallic oxygen evolving anode operating at high current density for aluminium reduction cells |
| RU2567429C1 (en) * | 2013-07-09 | 2015-11-10 | Общество с ограниченной ответственностью "Объединенная Компания РУСАЛ Инженерно-технологический центр" | Electrolyte for aluminium production by melts electrolysis |
| CN104451779B (en) * | 2014-12-17 | 2017-01-18 | 湖南创元铝业有限公司 | Aluminum fluoride control method of aluminum electrolytic cell |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5006209A (en) * | 1990-02-13 | 1991-04-09 | Electrochemical Technology Corp. | Electrolytic reduction of alumina |
| US5725744A (en) * | 1992-03-24 | 1998-03-10 | Moltech Invent S.A. | Cell for the electrolysis of alumina at low temperatures |
| US6258247B1 (en) * | 1998-02-11 | 2001-07-10 | Northwest Aluminum Technology | Bath for electrolytic reduction of alumina and method therefor |
| ES2381927T3 (en) * | 2002-10-18 | 2012-06-01 | Rio Tinto Alcan International Limited | Aluminum electrolytic reduction cells with metal-based anodes. |
-
2004
- 2004-02-18 WO PCT/IB2004/000431 patent/WO2004074549A2/en active Application Filing
- 2004-02-18 NZ NZ540408A patent/NZ540408A/en not_active IP Right Cessation
- 2004-02-18 CA CA2505285A patent/CA2505285C/en not_active Expired - Fee Related
- 2004-02-18 EP EP04712114A patent/EP1608798A2/en not_active Withdrawn
-
2005
- 2005-09-19 NO NO20054308A patent/NO20054308L/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| EP1608798A2 (en) | 2005-12-28 |
| AU2004213650A1 (en) | 2004-09-02 |
| WO2004074549A2 (en) | 2004-09-02 |
| CA2505285C (en) | 2012-07-17 |
| NO20054308L (en) | 2005-09-19 |
| NZ540408A (en) | 2007-04-27 |
| WO2004074549A3 (en) | 2005-05-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20170220 |